use std::collections::HashMap;

use crate::app_config::{AppType, McpServer, MultiAppConfig};
use crate::error::AppError;
use crate::mcp;
use crate::store::AppState;

/// MCP 相关业务逻辑（v3.7.0 统一结构）
pub struct McpService;

impl McpService {
    /// 获取所有 MCP 服务器（统一结构）
    pub fn get_all_servers(state: &AppState) -> Result<HashMap<String, McpServer>, AppError> {
        let cfg = state.config.read()?;

        // 如果是新结构，直接返回
        if let Some(servers) = &cfg.mcp.servers {
            return Ok(servers.clone());
        }

        // 理论上不应该走到这里，因为 load 时会自动迁移
        Err(AppError::localized(
            "mcp.old_structure",
            "检测到旧版 MCP 结构，请重启应用完成迁移",
            "Old MCP structure detected, please restart app to complete migration",
        ))
    }

    /// 添加或更新 MCP 服务器
    pub fn upsert_server(state: &AppState, server: McpServer) -> Result<(), AppError> {
        {
            let mut cfg = state.config.write()?;

            // 确保 servers 字段存在
            if cfg.mcp.servers.is_none() {
                cfg.mcp.servers = Some(HashMap::new());
            }

            let servers = cfg.mcp.servers.as_mut().unwrap();
            let id = server.id.clone();

            // 插入或更新
            servers.insert(id, server.clone());
        }

        state.save()?;

        // 同步到各个启用的应用
        Self::sync_server_to_apps(state, &server)?;

        Ok(())
    }

    /// 删除 MCP 服务器
    pub fn delete_server(state: &AppState, id: &str) -> Result<bool, AppError> {
        let server = {
            let mut cfg = state.config.write()?;

            if let Some(servers) = &mut cfg.mcp.servers {
                servers.remove(id)
            } else {
                None
            }
        };

        if let Some(server) = server {
            state.save()?;

            // 从所有应用的 live 配置中移除
            Self::remove_server_from_all_apps(state, id, &server)?;
            Ok(true)
        } else {
            Ok(false)
        }
    }

    /// 切换指定应用的启用状态
    pub fn toggle_app(
        state: &AppState,
        server_id: &str,
        app: AppType,
        enabled: bool,
    ) -> Result<(), AppError> {
        let server = {
            let mut cfg = state.config.write()?;

            if let Some(servers) = &mut cfg.mcp.servers {
                if let Some(server) = servers.get_mut(server_id) {
                    server.apps.set_enabled_for(&app, enabled);
                    Some(server.clone())
                } else {
                    None
                }
            } else {
                None
            }
        };

        if let Some(server) = server {
            state.save()?;

            // 同步到对应应用
            if enabled {
                Self::sync_server_to_app(state, &server, &app)?;
            } else {
                Self::remove_server_from_app(state, server_id, &app)?;
            }
        }

        Ok(())
    }

    /// 将 MCP 服务器同步到所有启用的应用
    fn sync_server_to_apps(state: &AppState, server: &McpServer) -> Result<(), AppError> {
        let cfg = state.config.read()?;

        for app in server.apps.enabled_apps() {
            Self::sync_server_to_app_internal(&cfg, server, &app)?;
        }

        Ok(())
    }

    /// 将 MCP 服务器同步到指定应用
    fn sync_server_to_app(
        state: &AppState,
        server: &McpServer,
        app: &AppType,
    ) -> Result<(), AppError> {
        let cfg = state.config.read()?;
        Self::sync_server_to_app_internal(&cfg, server, app)
    }

    fn sync_server_to_app_internal(
        cfg: &MultiAppConfig,
        server: &McpServer,
        app: &AppType,
    ) -> Result<(), AppError> {
        match app {
            AppType::Claude => {
                mcp::sync_single_server_to_claude(cfg, &server.id, &server.server)?;
            }
            AppType::Codex => {
                mcp::sync_single_server_to_codex(cfg, &server.id, &server.server)?;
            }
            AppType::Gemini => {
                mcp::sync_single_server_to_gemini(cfg, &server.id, &server.server)?;
            }
        }
        Ok(())
    }

    /// 从所有曾启用过该服务器的应用中移除
    fn remove_server_from_all_apps(
        state: &AppState,
        id: &str,
        server: &McpServer,
    ) -> Result<(), AppError> {
        // 从所有曾启用的应用中移除
        for app in server.apps.enabled_apps() {
            Self::remove_server_from_app(state, id, &app)?;
        }
        Ok(())
    }

    fn remove_server_from_app(_state: &AppState, id: &str, app: &AppType) -> Result<(), AppError> {
        match app {
            AppType::Claude => mcp::remove_server_from_claude(id)?,
            AppType::Codex => mcp::remove_server_from_codex(id)?,
            AppType::Gemini => mcp::remove_server_from_gemini(id)?,
        }
        Ok(())
    }

    /// 手动同步所有启用的 MCP 服务器到对应的应用
    pub fn sync_all_enabled(state: &AppState) -> Result<(), AppError> {
        let servers = Self::get_all_servers(state)?;

        for server in servers.values() {
            Self::sync_server_to_apps(state, server)?;
        }

        Ok(())
    }

    // ========================================================================
    // 兼容层：支持旧的 v3.6.x 命令（已废弃，将在 v4.0 移除）
    // ========================================================================

    /// [已废弃] 获取指定应用的 MCP 服务器（兼容旧 API）
    #[deprecated(since = "3.7.0", note = "Use get_all_servers instead")]
    pub fn get_servers(
        state: &AppState,
        app: AppType,
    ) -> Result<HashMap<String, serde_json::Value>, AppError> {
        let all_servers = Self::get_all_servers(state)?;
        let mut result = HashMap::new();

        for (id, server) in all_servers {
            if server.apps.is_enabled_for(&app) {
                result.insert(id, server.server);
            }
        }

        Ok(result)
    }

    /// [已废弃] 设置 MCP 服务器在指定应用的启用状态（兼容旧 API）
    #[deprecated(since = "3.7.0", note = "Use toggle_app instead")]
    pub fn set_enabled(
        state: &AppState,
        app: AppType,
        id: &str,
        enabled: bool,
    ) -> Result<bool, AppError> {
        Self::toggle_app(state, id, app, enabled)?;
        Ok(true)
    }

    /// [已废弃] 同步启用的 MCP 到指定应用（兼容旧 API）
    #[deprecated(since = "3.7.0", note = "Use sync_all_enabled instead")]
    pub fn sync_enabled(state: &AppState, app: AppType) -> Result<(), AppError> {
        let servers = Self::get_all_servers(state)?;

        for server in servers.values() {
            if server.apps.is_enabled_for(&app) {
                Self::sync_server_to_app(state, server, &app)?;
            }
        }

        Ok(())
    }

    /// 从 Claude 导入 MCP（v3.7.0 已更新为统一结构）
    pub fn import_from_claude(state: &AppState) -> Result<usize, AppError> {
        let mut cfg = state.config.write()?;
        let count = mcp::import_from_claude(&mut cfg)?;
        drop(cfg);
        state.save()?;
        Ok(count)
    }

    /// 从 Codex 导入 MCP（v3.7.0 已更新为统一结构）
    pub fn import_from_codex(state: &AppState) -> Result<usize, AppError> {
        let mut cfg = state.config.write()?;
        let count = mcp::import_from_codex(&mut cfg)?;
        drop(cfg);
        state.save()?;
        Ok(count)
    }

    /// 从 Gemini 导入 MCP（v3.7.0 已更新为统一结构）
    pub fn import_from_gemini(state: &AppState) -> Result<usize, AppError> {
        let mut cfg = state.config.write()?;
        let count = mcp::import_from_gemini(&mut cfg)?;
        drop(cfg);
        state.save()?;
        Ok(count)
    }
}
